Degradation modes of cermet-based selectively solar absorbing coatings

Rafi Gatt; Gunnar A. Niklasson; Claes-Goeran Granqvist

doi:10.1117/12.130495

25 November 1992 Degradation modes of cermet-based selectively solar absorbing coatings

Rafi Gatt, Gunnar A. Niklasson, Claes-Goeran Granqvist

Proceedings Volume 1727, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XI: Selective Materials, Concentrators and Reflectors, Transparent Insulation and Superwindows; (1992) https://doi.org/10.1117/12.130495
Event: Optical Materials Technology for Energy Efficiency and Solar Energy, 1992, Toulouse-Labege, France

Abstract

We have studied the degradation of cermet selectivity solar absorbing coatings produced by magnetron sputtering. The samples consisted of a reflector layer of molybdenum, a graded Mo-Al₂O₃ cermet layer, and an antireflection layer of aluminum oxide. The coatings were exposed to temperatures between 673 K and 1123 K in an atmosphere where the pressure was kept below 10^-4 Torr. The degradation of the solar absorptance was determined as a function of time and temperature. A remarkable stability at high temperatures in vacuum is reported. The optical properties could be interpreted within a multilayer optical model employing the Bruggeman effective medium theory for the cermet layer. It was found that the metal content of the cermet layer continuously decreased as the degradation proceeded. We assume that oxygen ions move through the amorphous aluminum oxide in microchannels and subsequently oxidize the molybdenum particles in the cermet layer. Theories for oxidation by anion movement are reviewed and used in order to interpret the experimental degradation kinetics.

Citation Download Citation

Rafi Gatt, Gunnar A. Niklasson, and Claes-Goeran Granqvist "Degradation modes of cermet-based selectively solar absorbing coatings", Proc. SPIE 1727, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XI: Selective Materials, Concentrators and Reflectors, Transparent Insulation and Superwindows, (25 November 1992); https://doi.org/10.1117/12.130495

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available